In power semiconductor devices, for example, IGBTs, in order to make high-speed turning off possible, freewheeling diodes are used for drawing excess carrier of the emitter sides of the IGBTs. In the related art, it has been general to form a freewheeling diode in a chip different from the chip of an IGBT, and connect the IGBT chip and the freewheeling diode chip with wire or the like, and organize them into a single module with a resin or the like.
Technologies for improving the trade-off characteristic between noise which is generated during a turn off switching operation and switching loss in an IGBT having a freewheeling diode are known (see the following JP-A-2009-55696 and JP-A-2013-78258 for instance). According to this type of technologies, in the case of having an IGBT perform a turn off switching operation, until the voltage between the collector and emitter of the IGBT reaches a DC voltage which is applied between the collector and the emitter, the change rate of the collector-emitter voltage is set to be large, and after the collector-emitter voltage reaches the DC voltage, the change rate is set to be small.
Recently, further scaling down of power semiconductor devices has proceeded, and the configuration in which a freewheeling diode is formed in an IGBT chip has been mainstreamed. Even in this configuration, in terms of the control properties, it is important to turn off the IGBT at high speed, and the above-mentioned technologies are technologies for improving the trade-off characteristic between noise and switching loss in the case of forming an IGBT and a freewheeling diode in different chips. In other words, the above-mentioned technologies are not technologies considering the characteristics of a reverse-conducting IGBT configured by forming an IGBT and a freewheeling diode in the same chip. Therefore, in the case of applying the above-mentioned technologies to a reverse-conducting IGBT, in speeding up turn-off, a certain effect can be obtained, however, recently, it has been demanded to further speed up turn-off of reverse-conducting IGBTs, and the above-mentioned technologies have a limit in speeding up turn-off of reverse-conducting IGBTs. In other words, even though the above-mentioned technologies of the related art are applied, there is a limit in improving the control properties of the reverse-conducting IGBT.